According to Library Hi Tech, glare comes in many forms caused by 'light sources within the field of vision that are of a higher luminance to other objects to which the eyes are adapted'.

Specular glare, another problem, is caused by lights from bright objects reflecting on to the screen and into the eyes of the user.

Another form of glare occurs when outside light penetrates the monitor glass and reflects off the phosphor layer behind the screen.

The resulting glare makes it difficult for the eyes to identify on-screen images causing users to constantly squint.

Another problem can be the build-up of static electricity within the CRT monitor which attracts dust particles which can irritate eyes and trigger skin allergies.

All these factors can contribute to reduced productivity.

To combat glare and dust, Polaroid recommends that all computer screens have a filter made of either wire mesh, plastic or glass.

It should also be electrically grounded to prevent static build-up.

While wire mesh filters are cheap, they are now less popular than glass and plastic models which have an optical coating to reduce glare.

Polaroid claims its AG-2000 is effective in reducing glare as the filters have multi-layer anti-reflection coatings which enhance contrast.

In addition, a conductive coating minimises static build-up.

All of the company's filters come with electrical grounding wires, effective for eliminating up to 98 per cent of static created by the monitor.